java program for prime number
Answers
Question:-
- Java code to check if a number is a prime number or not
Answer:-
package Coder;
import java.util.*;
public class PrimeCheck {
public static void main(String[] args) {
Scanner sc=new Scanner (System.in);
System.out.println("Enter a number");
int n=sc.nextInt();
int c=0;
for(int i=1;i<=n;i++)
{
if(n%i==0)
c++;
}
if(c==2)
System.out.println("Prime number");
else
System.out.println("Not a prime number");
}
}
Variable Description:-
- n:- to accept the number from the user as input
- i:- loop variable to run a loop from 1 to n
- c:- counter variable to count number of factors
Explaination:-
- The program runs a loop from 1 to n (where n is the number entered by the user)
- Each iteration, the program counts the factor of n
- if the count of the factor is 2 then it's a prime no.
- else it is not a prime number
•Output Attached.
Code:
import java.util.Scanner;
public class PrimeNumber {
static boolean isPrime(int number) {
int limit = (int) (Math.floor(Math.sqrt(number))) + 1;
for (int i = 2; i < limit; i++)
if (number % i == 0)
return false;
return true;
}
public static void main(String[ ] args) {
System.out.print("Enter a number - ");
int number = new Scanner(System.in).nextInt( );
System.out.println((isPrime(number) ? "Is" : "Not") + " Prime");
}
}
Sample I/O:
Case 1:
Enter a number - 12
Not Prime
Case 2:
Enter a number - 13
Is Prime